Compression riveter



May4,1943. F P FQRSS 2,318,071

I coMPREssIo'N RIVETER Filed Nov. 27, 1939 s sheets-sheet 1 Nq 1w 757; CNW-' ATTORNEYV May 4, 1943. F, P. FoRss coxsfPR'ssIoN RIVETER Filed Nov. 27

5 Sheets-Sheet 2 May 4, 1943.

Ilf. P. FoRss coMPREssIoNRIvETER Filed Nov. 27, 1939 3 Sheets-Sheet 3 BY v- ATTORNEY.

Patented May 4, 1.943

COllIPRESSION RIVETER Frithiof P. Forss, Aurora, Ill., assignor to Independent Pneumatic Tool Company, Chicago, Ill., a corporation of Delaware Application November 2.7, 1939, Serial No. 306,254

(Cl. 7S-48) 12 Claims.

This invention relates to riveting machines and more particularly to riveting machines of the compression type.

The invention is concerned with compression riveters of the portable character and has for its principal object the provision of a power generating mechanism which enables a relatively small and compact hand manipulated riveter to develop considerable power as required for cold riveting in metal airplane production and kindred work.

In accordance with my invention, the power generating mechanism referred to may take the form of a combined cam and lever action carried by the machine between its power applying and riveting elements, respectively. The cam is shaped and disposed to gradually diminish the unit of arcuate movement of the lever in the power stroke of the machine and thus greatly increase the power of the lever on the riveting element. This increase of power is sufficient to head and clamp a rivet on each power stroke of the machine, thus adapting the machine for production work.

A further object of my invention is to provide a cam which gives a relatively fast travel to the lever in its initial movement on a power stroke so as to quickly bring the riveting plunger into contact with the rivet.

A further object of my invention is to provide a novel form of throttle valve mechanism for controlling the admission and exhaust of pressure uid to and from the cylinders of the machine, said valve being so constructed that a spring pressure must be overcome by the operator to avoid sudden starting of the machine.

A further object of my invention is to provide an adjustable stop to regulate the travel of the plunger and thus adapt the machine for long and shorter rivets.

A further object of my invention is to provide a relief valve for controlling the applied pressure on the machine, and thus make the machine usable for rivets of diiferent ductilities.

The invention consists further in the features hereinafter described and claimed.

In the accompanying drawings- Fig. l is a longitudinal sectional view with parts in elevation of the compression riveting machine constructed in accordance with my invention;

Fig. 2 is a similar view taken on line 2-2 of Fig. l;

Fig. 3 is a cross sectional view with parts in elevation taken on line 3-3 of Fig, 1;A

Fig.4 -isa fragmentary longitudinal sectional View with parts in elevation taken on line 4 4 of Fig. 1;

Fig. 5 is a similar view showing the mounting for the plunger in its released position;

Fig. 6 is an end View of the parts shown in Fig. 4;

Fig. 7 is a fragmentary top plan view of a stop element to be later described;

Fig. 8 is a side view of the housing which mounts the riveting plunger;

Fig. 9 is a similar view of one to be later described;

Fig. 10 is a longitudinal sectional view with parts in elevation of the throttle valve, the latter being shown in a positionto supply pressure fluid to the main cylinder; p

Fig. 11 is a similar view of said valve, the latter being shown in a position to supply pressure fiuid to the auxiliary cylinder;

Fig. 12 is a view similar to Fig. 4 showing the stop adjusted to limit the stroke of the riveting plunger; and

Figs. 13, 14 and 15 are diagrammatic views showing the action of the power mechanismI and of Y the keybars the throttle valve, respectively.

The machine shown in the drawings is designed to head cold rivets of alloy steel or Durallumin, which rivets are used in the building of metal airplanes and require considerable power to clamp the metal sheets or plates together and 'form a proper head on the rivets. The machine shown is portable, being relatively light in Weight and compact and small in size for convenience in manipulation and holding in the hands of an operator.

The machine illustrated comprises a frame or i support l to `one end of which is secured a main power cylinder 2 and to the other end of which frame is secured a yoke element 3 having an anvil 4 in line with a riveting plunger'or ram 5. The latter is reciprocably mounted in the support I and is projected forwardly for heading a rivet and securely clamping the riveted plates together by a combined lever and cam action to be presently described. The yoke 3 is preferably made separate from the frame l, being bolted thereto by one or more bolts 6 as shown inFigs. 1 and 2. Y

The cylinder 2 contains a piston 'l and is closed at its rear end by a head casting 8 which also provides a guidel and support for a piston rod 9 connected at its forward end to the piston 'l as shown. 'Ihelrod 9 extends slidably through the head 8 into an auxiliaryV cylinder Il),y the Vlatter being secured to and closed at its forward end by said head casting 8.

The cylinder l5 is smaller in diameter than the main cylinder 2 and contains a piston II connected to the rear end of the rod 5. The rod 9 is provided with a pressure fluid passage I2 which opens into the cylinder I5 through the rear end of the rod and connects adjacent its front end with the cylinder 2 through a port 'I3 in the rod on the rear side of the piston I as shown. By this arrangement, pressure fluid supplied to the main cylinder 2 will enter the auxiliary 'cylinder il) and act simultaneously on the pistons in both cylinders to drive the pistons vforwardly on :a power stroke. The ow of pressure fluid to the cylinders is controlled by a manually operable throttle valve carried by the head `casting 8 between the cylinders 2 and IE) and which valve is detailed in Figs. 10 and 11 and will be later described. It is suilcient to say at this point that when the valve device is positioned as vshown in Figs. 1G and 14, the pressure fluid drives both pistons forwardly -on a power stroke. On the yother hand, when ythe valve device is positioned as shown in Figs. l1 and 1.5, the pressure iiuid enters the auxiliary cylinder I G on the front side of its piston li and returns both pistons to the beginning of the power stroke.

The lever and cam mechanism which transmits the power of the pistons to the plunger or ram 5 and multiplies the power to that required for a cold riveting operation is located in a nousing I4 provided by the frame or support I in advance of its connection with the 'cylinder 2. The power .lever I5 of this mechanism is fulcrumed at its upper end in said housing I4 on a fulcrum pin I6. The latter is mounted at its ends in the side walls I'I, I8-of the housing I4 and allows the lower end of said lever to be swung towards and from the plunger 5. A link I9 connects the lower or swingable end of the lever |5 to a pair of links 20, which project forwardly from the piston 'I. A pivot pin 2| provides the connection between the link I9 and the lever I5, the latter having a forwardly extending portion 22 to engage the inner end 23 of the plunger orY ram 5. The inner end 23 of the plunger is enlarged to provide a seat for a coiled spring 24 which keeps the plunger 5 in Contact with the lever I5 and causes the plunger to follow the i lever on the return stroke of the pistons 'I and I I.

The links 25, 20 lare pivotally connected to the piston 7 through `a pair of forwardly projecting apertured lugs 25, 25 on the piston anda cooperating pivot rod 26. The latter through the lugs and the links and is held from rotation by a screw 2'I which extends through the rod and is screwed into the adjacent end of the piston rod 9 at its clamp nut 28. The latter is screwed on the forward end of the piston rod 9 to clamp the piston I thereto as shown in Figs. l and 2.

The rod 25 provides a rotatable mounting for the links 2B, 2U, the latter being parallel and connected at their forward ends to the lever IS by a cross-pin 29. Said cross-pin 29 has its ends journaled in the links 20 and carries between them a roller which co-acts with a camshaped track-Way 3| xed in the housing` I4 above the links as show-n. The links 2|) are held in their assembled relation by a combined fastening and spacer element. The latter comprises a spacer member 32 tting between the links and screw elements 33 which extend into and engage the spacer member through the links as shown.

extends The cam-track 3| is on the under-side of a cam-block 34 which is secured in the housing I4 above the roller 30 by a screw and dowel arrangement shown in Fig. 1. The screw is marked 35 and the dowels are marked 36.

The operation of the machine so far described is as follows: The piston 'I is brought to the beginning of lits power stroke by admitting pressure fluid into the auxiliary cylinder Ii] on the forward side of its piston II. This brings the piston 'I adjacent to the head 8 and shifts the roller 30 to the start or low point a. (Fig. 13) of the cam-track. The lever I5 is swung rearwardly about its fulcrum I6 and reaches the positionshown at B in Fig. 13. The link I9 occupies the position shown at C and the plunger 5 due toits spring .24 follows the lever to the position shown at D. It may be remarked at thispoint that the spring 24 also holds the roller 30 against the cam-track 3|. Pressure uid is now admitted to the rear end of the cylinder 2 through the throttle valve heretofore referred to and both pistons are driven forwardly. This moves the roller 3|) forwardly along the camtrack 3|, the curvature or shape of which is designed to progressively diminish the unit of arcuate movement of the lever I5 towards the plunger 5 and thus ngreatly increase the power on the plunger. This increase in power will be apparent from an inspection of Fig. 13.

The left hand group of numerals l to 6 inclusive in Fig. 13 represent equal divisions of the power stroke of the pistons from E to E. The right hand group of numerals 1 to 6 inclusive show the extent of the arcuate movement given to the lever I5 for each corresponding unit of movement 1 to 6 of the pistons. It will be noted that the units of arcuate-movement of the lever I5 decrease rapidly in the power stroke of the pistons and thus cause the lever I5 to build-up a considerable pressure on the plunger V5 as the roller 5E] travels along the cam-track 3| from its low point a to its high point b. This shortening of the throw of the lever I5 as compared to the stroke of the pistons 'I and II is brought about by the change 'in angularity between the lever I5 and the link I9 due to the curvature of the cam-track 3|. Hence, the ratio per unit of movement of the lever i5 and the pistons increases on the power stroke of the pistons and considerable power is available for the riveting stroke of the plunger. In the particular embodiment shown, it is possible with a one-half inch travel for the plunger to obtain an ultimate pressure at the plunger of a ratio of more than 8 to l over the pressure due to the areas of the pistons and the pressurein :the supply line.

It will -be noted that the rst units of the travel of the lever I5 is of a greater extent than the remaining units of movement. This causes the lever I 5 to move faster in the initial travel of the roller 30 along the track-way 3| and hence the plunger 5 is brought quickly against the rivet to be operated upon. The remainder of the travel of the lever is progressively less per unit of movement and considerable pressure is exerted on the lplunger through the lever per unit of travel of the pistons. With both .pistons under pressure, more power is available than should only one piston be relied upon. As further yevidence of the increased power developed by the machine, attention is called to the ratio of travel of the pistons and the plunger, respectively. In Fig. 13 this ratio is about 4 to V1. In practice, the machine has sufficient power to properly i rivet and clamp on each power stroke of the pistons, thus allowing the tool to be moved rapidly from one riveting operating to another in the use of the tool.

In the machine shown, all of the load is carried at the points F, G, which points are at the camblock 34 and fulcrum pin I6, respectively. With a heavy cam-block and a heavy fulcrum pin, both securely anchored in the frame I, no strains are transmitted to the pistons. The power load is carried by the lever I and the link I9. These parts are heavy one-piece solid elements and thus adequately take the power strains.

As shown in Fig. 3, the link I3 is bifurcated at its opposite ends to straddle the lever I5 andthe roller 30, respectively. At the roller, the link I9 has relatively heavy extensions 31, 31 which closely iit against the sides of the cam-block 34 to prevent lateral or side play of the parts. These extensions` as shown in Fig. l, are arcuate in shape to retain contact with the sides of the cam-block in the swinging motion of the link I9.

The roller 33 is mounted on bearing rollers 38, 38 for ease in operation and to reduce friction. As shown in Fig. 3, the cage elements 39, 39 for the bearing rollers embrace the sides of the roller 30. The latter is as wide as the cam-block 34 to insure full pressure contact of the roller 33 with the cam-track 3I.

As shown in Fig. 2, the lugs are integral with the piston 1 and the latter has cylindric recesses 48 at the outer sides of the lugs and in line with the bores thereof so that the pivot bar 28 may be readily inserted into and be withdrawn from the lugs in assembling and disassembling the machine. Also, the lugs 25 are spaced apart to provide a recess for the clamp nut 28 and the holding screw 21.

The pistons 1 and II are each equipped with replaceable leather cup packings 4I, 42, respectively, to engage the inner walls of their associated cylinders 2 and Ill. The auxiliary cylinder I0 is preferably made in one piece as shown and has a threaded connection with the head casting 8. A threaded ring 43 is employed to clamp the cylinder II) to the head 8, as depicted in Figs. l and 2. By this arrangement, the auxiliary cylinder I0 may be easily removed for inspection or adjustment.

Also, as shown in Figs. 1 and 2, a bearing bushing 44 is tted in the head 8 for the piston rod 9. The power cylinder 2 is secured at its ends to the frame I and the head 8, respectively, in any desired manner. Screw bolts and lugs on ythe respective parts may be employed for these connections as in portable tool design. The frame I is constructed to take standard yokes. In this connection, it is pointed out that the frame has a forwardly projecting integral web portion 45 to which the yoke is secured by the bolts 6, the yoke being bifurcated as at 46 to straddle the web as shown.

The mounting for the plunger 5 is releasable so that plungers may be quickly and easily removed for changing. In the embodiment shown, the plunger 5 is reciprocable in a housing 41 which is insertible into a channel-way 48 provided in the underside of the frame I forwardly of the lever I5. The complementary flat side walls 49, 50 of the housing 41 and the channel 48 t against each other when the parts are assembled as shown in Figs. 4 to 6 inclusive. The housing 41 carries a tail piece 5I which projects rearwardly and serves as a closure for the open lower portion of the housing I4 in the region of the lever I5 and the inner end of the plunger 5 as showninFig. 1.' f Y g The housing 41 is provided in each side wall 49 with a longitudinally extending'groove 52 and a number of slots 53 spaced along the groove and opening into the same from above. The grooves and the slots open laterally through the side lwalls of the housing and the slots alsoopen through the upper surface 54 of said housing. Riveted or otherwise i'lxedly securedto the side walls 50 of the channel-way 48 are key-bars 55, 55. These bars are alined horizontally'and each bar has an equal number of notches which provide lugs 51 on theloars.v The lugs 51 are located in the grooves52 out of line with the slots 53 when locking the housing 41 in the channel 48 as shown in Fig. 4. To make this connection the housing 41 is rst positioned below the channel 48 in substantial parallel relation thereto with slots 53 in registration with the key-lugs 51. The'housing 41 is now moved' bodily upward into the channel 48, the lugs 51 passing through the slots 53 and into the grooves 52. YThe upward movement of the housing 41 is stopped on contact of the lugs 51 with the bottoms of the grooves 52 below the slots 53, whereupon the 1 housing 41 may move forwardly in a longitudinal direction to carry the slots 53 out ofY registration with the lugs 31. This locates the lugs 51 below the portions of the gro0ves 52rvbeyond the slots 53 and the housing is interlocked with the frame I With the plunger 5 in lineA with the operative end of the lever I5. It should be remarked-here that the plunger 5 is placed Ain thebore of the housing 41 before the latter is inserted Yinto the channel 48. Also, the spring 24,is applied to the plunger before the latter-is inserted into the channel 48. y

The foregoing locates the spring in 'its operative position between'the headed inner end 23 of the plunger and the housing 41. Infmounting the assembly in the frame, it is necessary to keep the housing 41 pressed back against the spring to aline the slots 53 with the vkey-lugs 51. When these lugs reach the bottomof the grooves 52, the housing 41 is released and the spring 24 expands to move the housing forwardly to interlock the housing with the frame. This forward movement of the housing 41 is stopped by contact of the rearmost lugs 51 with the ends of the grooves 52 which are closed for this purpose. `The pressure of the spring 24 keeps the housing 41 interlocked with the lugs 51 and the housing is retained in the frame with the plunger `5 in line with the lever I5.

To remove the plunger, the housing 41 is pressed back against the spring 24 until the lugs 51 register with the slots 53 whereupon the housing is free of the frame I yand may be dropped setting it to operate on shorter rivets, I provide a stop element 58. The latter is mounted in the frame I adjacent the rear end of the plunger 5 and is projectible into and out of the path of movement of the headed inner endv 23 of said plunger. In Fig. 4, thestop 58 is shown out of the path of the plunger, being held in this position by its cross-head 59 at the upperlendl `of .the

A'stop .spamiing a .kerf 60 in the outer end of the stop mounting 6l. When the head -59 is "turned to 1enter the kerf 69,1th'e spring 62 about the stop 58 projects :it inwardly into 'the path of the plunger '5. This is done when the plunger is pulled forwardly to position its headed inner end beyond the stop as shown in Fig. 1.2. When the parts are so positioned, the forward end of the plunger 5 reaches a shorter rivet and' the extent -of the plunger travel is accordingly shortened.

The throttle valve as detailed in Figs. 10 and l1 comprises a tubular -housing 63 mounting a reciprocable valve element 64. The latter has a stem or-a rod-65 lto which is secured a pair of valve members 66, 61 in-spaced relation. The members 66, v61-are cylindrical and slidablyengage the inner cylindrical wall -of the housing A63 as shown. The members 66, 161 are spaced apart axially of the Vrod 65, the upper member 66 controlling the admission and exhaust of pressure fluid into and out-of the main cylinder l2, while the lower member 61 has a similar function for the auxiliary cylinder I8.

The main inlet por-t 68 in the housing 63 is located between the va'lve members 66, 61 and is connected to the air hose socket 69 in the head 8 through which the pressure fluid is supplied to the tool. The ports 66 and '69 are joined by an interposed passage-way 8a in the head 8 as shown in Fig. 2. The valve members 66, 61 are spaced apart a fixed distance so as not to close the inlet port v68 when -opening or closing the ports for 'the cylinders 2 and l 0.

Ports 1-9 and 1I in the housing 63 are connected to the main cylinder 2 Aon the rear side of the piston 'l through -a port 12 in fthe head casting 8 as shown in Fig. 2. Ports 1-5 and 1| are Vopened and closed by the valve member 66. The llatter is chambered as indicated at' 13 to accommodate a pair-of coiled rsprings 154, 1l51anda sleeve 16 which is slidably mounted on the stem or rod 65 between the valve member 66 and a shoulder 11 on said stem. The first mentioned spring 14 encircles the sleeve 16 and -is vlong enough to seat `at Yits lower end against the valve member 66 at the bottom Yof the chamber 13, and at its upper 'end against a sore-w plug 1'8 which closes the 'upper end o'f -thehous'ing 63. The plug 18 also provides a bearing and' guide for the valve stem 65 as shown. The other spring 15 is smaller in die ameter-and ts about the portion of the rod 65 lbetween the rlower -end of the sleeve 16 and the bottom of the chamber 13 as shown 'in Figs. 10 and 11. The purpose o`f this spring arrangement is to move the valve device 64 downwardly when The last mentioned function is brought about A,

by having the two inlet ports 10, 1i `for the cylinder 2. The `lower port 1l 'has a smaller Varea than the upper port 10 and is openedby'the valve member `66 in advance of the port 18. Hence, when the valve element 64 is raised by the operator, the smaller port 1l is opened first and a smaller amount-of air pressure `is admitted tothe cylinder 2 to start the piston 1 on the power stroke. The sleeve 16 Yfollows upwardly with the stem '65 until stopped by contact Withthe plug 18. The `port T0 is -still closed yby the valve member 66 making it necessary for the operator to compress .the in-ner spring 15 to open the port 18 to supply the 'cylinder 2 with m11 air pressure.

Therme stem es is raised by la lever '19 niicrumed on the exterior of the head `casting 8 between the cylinders -2 and i8 as shown in Fig. 1. The casting i8 has a lug 88 .to mount the fulcrum. The longer arm of the lever 19 @verlies `the cyl- -inder I0, the arrangement being such that the lever-extends lengthwise 'of the cylinder as shown. The shorter arm -of the lever 19 is connected to fthe upper -end ol the valve rod 65 by a pivot pin 82, the valve rod being bifurcated to accommoda'te the 4adjacent end of the lever 19.

The valve member 261 controls a pair of vertically spaced ports 83, l8'4 located in the housing 63 adjacent its lower end as shown in Figs. 10 and 11. The por-t I83 Vis the inlet port for the auxiliary cylinder 18, while 'the port 84 is .the exhaust port rfor sa'id cylinder. The port 83 is connected to the cylinder "I0 by a passageway 8b in thelhead element 8 as shown in Fig. 2. The housing A63 is v:provided at its lower end with a port 85 which-connects the-bore ofthe housing with crossports 86 -in the extremelower-end of the housing. The exhaust'ports for the'cylinder2 lin the Ahousing 63 are marked 81, 81. 'These portsare above the inlet ports 10, 1-'I -and are opened and closed by ithe `valve member l6 6.

through the bore-ofhousingi with-the inlet port 83 for the auxiliary cylinder I9 and fluid .pressure is admitted .to the forward end of said cylinder .to return the'pistons to the beginning of the power stroke. The exhaust ports 81 are at this ltime, for .the main cylinder 2, uncovered by thevalve member 66 and said cylinder exhausts to theatmosphere through the exhaust outlet 89 for the tool in the `head element. Thelatter is provided -with a passageway 8c connectingthe exhaust outlet 89 with the exhaust ports^81 and 86, respectively, as indicated inFigs. 1'4 and 15. The cylinder I0 on the rear side ofits-piston also exhausts at Vthistime through the main cylinder 2,

passage-Wayin inthe piston rod 9 providing the connection. The .operating lever 19 is at this time inthe dotted vline position shown in Fig. l, being 'heldin'that position by the springs 14, l15.

To -dri-Ve'thepistons Vforwardly the `lever V19 is Vmoved towards-the .cylinder l0. This-raises the Valve rod 65 to fthe position shown in Fig. 10 and the valve member 61 is raised to Aclose lthe inlet port 83 and open theexhaust port`8'4. This relieves the pressure on ythe `forward side of the piston I'l and closes the exhaust ports f81`before openingthe inlet ports 10, 11.

vThe passage arrangementbetween the throttle 'vali/e764 and the pistons 2 and I8 .is shown in diagram in Figs. 14 and 15. The passage-Ways are suitably legended in these figures sothat the use of reference characters to indicate 'them is deemed unnecessary. Fig. '14 shows the valve 64 positioned as in Fig. 10, while Fig. 15 lshows thevalve positioned as in 'Fig."11.

The operations above described-arerepeated in alternation for-each .riveting-action. The lever 19 is released toreturnthe plunger' 5to the beginning of its'riveting stroke, whereas the lever is movedtowards the cylinder l0 to1drive the plunger'forwardly. 'The `lever 19 is mounted as shown to be readily accessible and operable with with'his otherhandat the frame the tool being'held intherposition .desiredito engage the Vwor-k between the zanvil .r4 vandthe .'plunger 5.

The tool may be moved along the work from one riveting point to the next; and complete a riveting action on each power stroke of the plunger. When riveting steel or other hard metal rivets the full power of the machine will be employed. To adjust the machine tooperate on softer-rivets, the power factor of the machine is reduced to that required for the softer metal. This is accomplished through the medium of an adjustable relief valve shown at S in Fig. 2.

The valve fixture 90, Vin theembodiment illustrated, comprises a body member 9i screwed into the head 8 between the cylinders 2 and I0 ata duct 92 which leads to the inner end of the 'cylinder 2. The body member 9| has a tapered bore to accommodate a complementaryshapedfvalve plug 93. The latter is held in seated relation within thebore of the body member Si -by a coiled spring 94 bearing at one end against the plug 93 in a recess therein and at its opposite end against a cap-member 95 which closes the outer'end of the body member 9i. The capmember 95 has screw threaded connection-with the body member 9| for adjustment axially to vary the tension of the spring 94 on the valve plug 93. The cap-member 95 is also provided with a number of vent openings 96 which release the pressure in the cylinder 2 when the' valve element 93 is raised ormoved outwardly against its spring 94. The cap 95 maybe knurled or otherwise formed to facilitate turning it and any suitable graduation arrangement may be provided to indicate an adjustment for any given pressure. It will be apparent from the foregoing that by settting or adjusting the valve member 93 to the pressure desired themachine will be operated at that pressure. This is, of course, less than the maximum pressure of the machine which pressure is available on vsetting thereliefvalve' justable for short and long rivets which factor contributes to the eiiciency of the mechanism as a commercial product. In keeping with this purpose, the yoke 3 is removably secured to the frame l so that yokes of various designs may be employed with the machine to give it more universal use. Y ,j

Another 4feature of importance is the provision of a slot I3a. in the outer surface of the rod 9 at the port I3. This slot extends to the adjacent surface of the piston 'l and connects the passage l2 with the cylinder 2 when the port i3 is within the bushing 44 and is covered thereby. Hence, the auxiliary cylinder I0 is not cut-off from the main cylinder 2 when the piston 1 is against the bushing 44 as when at the beginning of the power stroke. The slot 13a opens into the cylinder 2 at this position of the piston 1 and the cylinder l0 is supplied with compressed air from the cylinder 2 as soon as the throttle valve 64 is actuated to connect the tool with the compressed air supply. This gives a smooth and even starting movement for the pistons because both are acted on simultaneously by the motive uid and not one in advance of the other which would occur should the opening of the port I3 be delayed. The outer surface of the rod 9 at the port I3 may be milled flat to aid the connection with the cylinder 2 when the piston 'l is directly against the bushing 44 or the boss which supports it.

The details of construction and arrangement of parts shown and described may be variously changed and modified without departing from the spirit andl scope of my invention, except as pointed out in the annexed claims.

I claim as my invention:

l. In a riveting machine, the combination with a support, of a cam-track and a riveting plunger carried by the support, said cam-track being stationarily mounted on said support, a lever fulcrumed on the support between the cam-track and the'plunger, va roller, a reciprocable power element having a straight line movement on the support vwith the center line of the movement parallel to the'plunge'r and disposed between the cam-track and the fulcrum ofthe lever, and links connecting` the rollervto the power element and to the swingable end of the lever, respectively, for Aforcing the lever with an increasing power against the plunger in the travel of the roller along the cam-track towards the lever. I

2. Inv a riveting machine, the combination with a support, of a cam-track and a riveting plunger mounted on the support,said cam-track being stationarily mounted Von said support, a lever fulcrumed onthe support between the cam-track and the plunger, a roller, power means for moving the roller along the cam-track towards the lever, pivotally connected rs't and second links, the rstlink connecting the roller Yto the power means and the second link connecting the roller to the swingable endr of the lever for forcing the lever with'an increasing power against theY plunger in the movement of the roller alongy the camtrack towards the lever, spring means acting through the plunger ffor holding the' plunger against the lever and the rroller against the camtrack, and auxiliary power means acting through the first mentioned link for moving the roller to its starting position on the cam-track following the power stroke of the lever on the plunger.

3. In a riveting machine, the combination with a supportfof a cam-track and a plunger mounted on the support, said cam-track being stationarily mounted on said support, a lever fulcrumed on the support between the cam-track and the lever, a roller, main and auxiliary pistonsV connected for movement in unison, links connecting the `roller to the main pistonand to the swingable end of the lever, respectively, for forcingthe lever withV an increasing power against the plunger in the movement of the-roller along the cam-track 'towards the lever, and valve means for controlling the ow of pressure fluid to the 4pistons whereby both pistons may be placed under powerv when moving the roller towards the lever and only the auxiliary piston being placed under cylinder to the main cylinder on the same` side of their respective pistons, links connecting. the roller to the piston of the main cylinder and to the swingable end 'of the` lever,'respectively, for forcing the lever against the plunger in the travel of the roller along. the cam-track towards the lever, and valve. means for admitting pressure fluid to the main cylinder 'when placing both pistons under power for movingv the roller towards the lever and to the auxiliary cylinder only when moving the roller in the opposite direction.

5. In a riveting machiner the combination with a support, of, a riveting plunger, power means carried by the. support tor imparting a riveting stroke to the plunger, a housing providing .a reciprocable mounting for the plunger, and interengageable means on the housing and the supy port, respectively,l for ,releasably connecting the housing to the supporti and holding the plunger in operative relation: to the power means.

6. In a riveting machine, the combination with a support, ot a riveting plunger, power means carried by the supportv for imparting a riveting stroke to the plunger, a housing providing a reciprocable mounting for lthe plunger, and interengageable lugs. and slots on; the support and the housing, respectively, for releasably'connecting the housing to the support and holding the plunger inoperative relation-to the power means.

'7. In a riveting machine, the combinationwith a support, of a rivetingplunger, power means carried by the support lfor imparting a riveting stroke. to the plu-nger, a housing providing a reciprocable mounting for the plunger, key elements carried: bythe support, intersecting grooves and slots in thev housing to receive thev key elements for releasably connecting the housing to thesupport and forliolding the plunger in operative relationto the power means, and spring means for holding thevhousing in connected rela.-

tion with the key elements.

8. In a riveting machine, the combinationwith a support, of a cam-track anda riveting plunger carried by the support, said cam-track being stationarily mounted on said support, a lever fulcrumed on the support between the cam-track and the plunger, a roller, power means for moving the roller along the cam-track, a link connecting the roller to the swingable end of the lever for forcing the lever withan increasing powerA against the plunger in the travel of the roller along the cam-track towards the lever, and a stop carried by the support for adjustment into and out of the path of the plunger for controlling the stroke thereof.

9. In a riveting machine,A the combination with a support, of a riveting plunger carried by the support, a power cylinder containing a piston mounted on the support,4 means for transmitting the power of the piston tothe plunger for imparting a riveting stroke thereto, and valve means for controlling the flow or pressure nuidtosaid cylinder, said' valve means having a manually operable movable valve member and a number of inlet ports controlled thereby, said ports beingof diierent sizes and arranged with the smaller port to be opened first to control the amount of pressure fluid admitted to the cylinder in the initial starting of the piston on its power stroke.

10. In a riveting machine, the combination with a support, of' a riveting plunger carried by the support, a power cylinder containing a piston mounted on the support, means for transmitting the power of the piston to the plunger to impart a rivetingV stroke thereto, valve means for controlling the flow of pressure uid to said cylinder, said valve means having a manually operable valve member and cooperating inlet ports of different sizes with the smaller port to loe opened firstto control the amount of pressure admitted to the cylinder inthe initial movemen-t of the piston on its powery stroke, a main spring for normally urging the valve member to a position closing said ports, and an auxiliary spring and a co-acting abutment therefor to exert an additional resistance to the opening of thel valve member following vthe opening of said smaller port.

l1. In a riveting machine, the combination with a support, of a riveting plunger, power means for imparting a riveting stroke to the plunger, said power means Vhaving rst and secondcylindersboth carried byv theY su-pport and each containing a piston, afrod connecting the pistons for movement in unison, a tubular bearingfor the rod between the pistons,valve means for admitting pressure fluid to the -rst cylinder, said rod having a passage-Way therein opening intothe second cylinder on the side of the piston `facing away from the first cylinder, a port' in the. rod for connecting the passage-way with the rst cylinder, and a slot in the rod' at said' port for connecting the same with the rst cylinder when the port is within and covered by the bearing.

1'2. In a riveting machine, the combination with a. support, of a riveting plunger slidably carried by said support, a cam-track stationarily mounted on the support, said cam-track extend ing in. thev same general direction as the plunger and oiset wholly to one side thereof, a lever fulcrumed atl one end'on the support between the camftrack and the plunger andhaving its swingable end engageable with the plunger, a roller, power means mounted on the support for moving the roller alongthe cam-track, and links connecting the roller to the power means and to the swingable end of the lever, respectively, tor forcingv the lever with an increasing power against the plunger inthe travel of the roller along the cam-track towards the plunger.

FRII'HIOF P. FORSS. 

